Urinary leukotriene E4 in children with wheezing associated respiratory illness from influenza infection

Background: Influenza virus can cause bronchiolitis and recurrent wheezing in young children. Although the pathophysiology is unclear, leukotriene is thought to play an important role.

Objectives: We conducted a prospective case-control study to measure urinary leukotriene E4 (uLTE4) levels in children with wheezing associated respiratory illness (WARI) from influenza infection, compared to children without respiratory tract infection and to identify the association between clinical features and uLTE4 levels in influenza-infected children.

Methods: Nasopharygeal secretions from patients less than 6-years-old hospitalized due to WARI were tested for influenza virus by RT-PCR. The uLTE4 levels were measured in the patients with influenza infection and compared with normal controls. The correlation between clinical features and uLTE4 levels was also studied.

Results: The study included 10 patients with influenza infection (median age 23.5 months) and 10 children as control group (median age 23 months). The uLTE4 levels were not significantly different between influenza and control group; 191.63 ng/mM creatinine (IQR 162.57-244.25) vs. 132.32 ng/mM creatinine (IQR 93.79-215.65), respectively (p = 0.096). There was no significant correlation between uLTE4 levels and clinical features including pulmonary index, eosinophil count, and length of hospital stay.

Conclusion: The uLTE4 level does not increase in pediatric patients with wheezing associated influenza infection and does not correlate with clinical features during infection. Although there is a trend towards increased uLTE4 in influenza patients and a correlation to the pulmonary index, the small sample size may have altered the significance of these results.